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LR RWD vs LR AWD Efficiency/Range

Discussion in 'Model 3' started by Hank101, Feb 7, 2019.

  1. Hank101

    Hank101 Go Tigers!

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    Is there a difference between the two, assuming both have the same wheel type?
    Thanks,
     
  2. chronopc

    chronopc Active Member

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    Yes, the LR RWD gets better efficiency/range.
     
  3. ℬête Noire

    ℬête Noire Active Member

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    It depends on the use but RWD is roughly 10% better. Not quite that much at highway cruising speeds but driving at lower speeds the RWD can drop its Wh/mile much lower than the AWD can, as the front motor just isn't as efficient so when it kicks in as normal course of driving it puts a floor on your Wh/mile efficiency.
     
  4. SageBrush

    SageBrush 2018: Drain the Sewer

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    What is the AWD range result by EPA testing ?
     
  5. lukex4

    lukex4 Member

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    • Informative x 3
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  6. SageBrush

    SageBrush 2018: Drain the Sewer

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    The tyre question is a very good one I am not sure of the answer to. So with that big caveat in mind here are the EPA results:
    Use the combined MPGe for overall efficiency and the highway MPGe for range. So e.g, the AWD range is 120/132 that of the LR.

    upload_2019-2-8_7-22-8.png
     
  7. SageBrush

    SageBrush 2018: Drain the Sewer

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    Is the Model 3 AWD in the list ? I may be going blind ...
     
  8. mswlogo

    mswlogo Active Member

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    Yes. Long Range Dual LRD
     
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  9. lukex4

    lukex4 Member

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    Yes, Teslike calls it "LRD" instead of the more common "AWD" for some reason...
     
  10. mswlogo

    mswlogo Active Member

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    So he can differentiate SRD,LRD,MRD in few letters.
     
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  11. SageBrush

    SageBrush 2018: Drain the Sewer

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    #11 SageBrush, Feb 8, 2019
    Last edited: Feb 8, 2019
    Ah, thanks.

    So 423/455 = 93%. About a 7% hit on highway range.
    The "real world" difference can be expected to be less because the EPA test has a series of decelerations that are not usually present in highway driving and most people drive faster than the 48 mph the EPA test average works out to, so the car differences in weight and drivetrain are diluted by higher but equal Aero losses.
     
  12. SageBrush

    SageBrush 2018: Drain the Sewer

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    We can improve the estimate for 68 mph highway driving by noting that there is 69 Wh/mile more Aero losses compared to 48 mph

    Presuming that the battery is 76 kWh
    the low speed LR is consuming 76,000/455 = 167 Wh/mile
    the low speed AWD is consuming 76,000/423 = 180 Wh/mile

    At 68 mph the LR would consume 167+69 = 236 Wh/mile
    At 68 mph the AWD would consume 180+69 = 249 Wh/mile

    So the AWD has better than 236/249 ~ 95% of the LR range (since we have not corrected for the absent decelerations.)
     
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  13. ℬête Noire

    ℬête Noire Active Member

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    It's not that more common. :p Used to be LRD / LR-D was at least as common of not more-so. That's why my sig reads the way it does. Expect it to swing back again, too, if Tesla ends up shipping a Standard Range Dual Motor.
     
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  14. lukex4

    lukex4 Member

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    I guess you're right that when Standard Range is out, SRD/MRD/LRD might be more common.

    But for now...
    ;)

    [​IMG]
     
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  15. ℬête Noire

    ℬête Noire Active Member

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    1) AWD refers to both P and D
    2) "Title" is a pretty crappy filter check on this.
     
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  16. HyperionMark

    HyperionMark Member

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    Is there any reason we can't see the efficiencies of the two converge through software updates (at least for chill mode)? I guess what I'm asking is, in a certain mode, is there any reason they can't just put the front motor to sleep unless you accelerate hard? I believe they even called it "torque sleep" in the S. I realize the dual motor has additional weight, about 240ish lbs I believe, but the current differences in the range/efficiency seems more than it should under such a small weight difference.
     
  17. Jonah125

    Jonah125 Member

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    Possibly an additional 17 Kg passenger would not be welcome on a long trip.
     
  18. Jan Fiala

    Jan Fiala Member

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    And why does S dual motor have a better range than S rear wheel drive? It doesn't make any sense,does it?
     
  19. SammichLover

    SammichLover Active Member

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    Because the S's front motor (and rear motor in the non-P) is more efficient than its rear motor. It is the same basic type of motor, induction, but it is also newer design. Plus the RWD S's motor is quite large, meaning they end up with similar vehicle weights. You can see the effect of this when you go to the P versions which use the older, larger drive unit from the RWD S and have worse range even when you're not stomping on it.
     

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